There are several different reasons that could be causing sleep disruption for you.
First, stress, anxiety, and depression
are all common causes of trouble staying asleep throughout the whole night. If you have any symptoms consist with one of these problems, you should talk to a counselor or to your primary care doctor
to help you deal with them.
Second, drinking alcohol or coffee (or other caffeine-containing beverages) in the afternoon or evening may impair your sleep architecture, leading to frequent reawakening while asleep.
Third, there are several common medications that can impair sleep architecture. These include medications that are commonly taken for allergies and cold symptoms, such as Benadryl. If you are taking any of these medications, this might be the cause of your trouble.
More serious medical problems can also impair sleep. For example, sleep apnea
is a common cause of frequent awakening during the night. If you are overweight or if you snore while sleeping, or if you constantly feel tired during the day despite sleeping all night, then sleep apnea is a possibility and you should see your primary care doctor to get that checked out. If your doctor suspects sleep apnea, they will refer you for a sleep study to confirm the diagnosis.